1. Field of the Invention
The present invention relates to a flat panel display device.
2. Description of the Related Art
There are merchandized products of ultra-large display systems for example a large screen multi-projection system using projection units in which plural projectors such as three CRTs or liquid crystal displays for RGB are arranged in vertical and horizontal directions. A system utilizing plural LED array panels composed flat is also available for the ultra-large display system. The former display system has a very large depth from the front thereof and therefore requires a lot of time and labor to assemble it. The latter display system involves a great difficulty in adjusting the tones and luminance of respective panels. Under such circumstances, there are attracting attentions as promising next generation ultra-large display devices e.g., units consisting of flat panel display devices such as organic electroluminescence devices, and electron emission devices such as FEDs (field emission display devices).
The organic electroluminescence device utilizes an organic compound material exhibiting electroluminescence (hereinafter also referred to as xe2x80x9cELxe2x80x9d) that is light-emission in response to the application of a current. Each organic EL device has a thin film made of an organic EL compound material as a light-emitting layer (hereinafter referred to as xe2x80x9corganic light-emitting layerxe2x80x9d). An organic EL device which can be driven with small power has a configuration in which an anode, an organic EL catalytic layer, and a metal electrode serving as a cathode are sequentially formed on a substrate. For example, an organic EL catalytic layer is a multi-layer element comprised of a single organic light-emitting layer or a medium having three-layer structure consisting of an organic hole transport layer, an organic light-emitting layer, and an organic electron transport layer or a medium having two-layer structure consisting of an organic hole transport layer and an organic light-emitting later and carrier (electrons or holes) injection layers or block layers appropriately inserted between those layers.
Flat panel display devices utilizing organic EL devices are self-emission devices having an image display array comprised of a plurality of light-emitting pixels which are organic EL devices provided in rows and columns crossing each other.
Whereas, flat panel display devices utilizing electron emission devices are known as flat type light-emitting display devices having an array of cool-cathode type electron emission sources whose cathodes are not required to be heated. Electron emission devices as electron emission sources of FEDs include devices having a metal-insulator-semiconductor (MIS) structure and devices having a metal-insulator-metal (MIM) structure.
As shown in FIG. 1, an electron emission device having the MIS structure has a diode structure in which a top electrode 15 that is a metal thin-film electrode on the top is at a positive potential Vd and in which a bottom electrode 11 that is an ohmic electrode on a backside substrate 10 of glass is at a ground potential. When the voltage Vd is applied between the bottom electrode 11 and top electrode 15 to inject electrons into an electron supply layer 12, electrons move in an insulator layer 13 toward the top electrode 15. Since a diode current Id flows and the insulator layer 13 has a high resistance, a major part of the applied electric field acts on the insulator layer 13. Some of electrons that have approached the top electrode 15 pass through the top electrode 15 because of the presence of the strong electric field to be emitted into the external vacuum. Electrons xe2x80x9cexe2x80x9d emitted by the top electrode 15 of the electron emission device (emission current Ie) are accelerated by a high acceleration voltage Vc applied to a collector electrode (transparent electrode) 2 provided on a front faceplate 1 in a face-to-face relationship with the same and are collected by the collector electrode 2. When the collector electrode is coated with a luminescent material 3, visible light associated with the element will be emitted.
As shown in FIG. 2, in a matrix type flat panel display device formed in a matrix-like configuration in which top electrodes 15 and bottom electrodes 11 are orthogonal to each other, a plurality of electron emission devices having the MIS (or MIM) structure are constructed by sequentially forming a bottom electrode, a semiconductor (or metal) electron supply layer, an insulator layer, and a top electrode on a substrate in each of regions where the top and bottom electrodes intersect each other.
As shown in FIG. 3, a front-side substrate 1 has a transparent collector electrode 2 made of an indium tin oxide (so-called ITO), a tin oxide (SnO), a zinc oxide (ZnO) or the like provided therein and receives electrons emitted by electron emission devices S on the backside substrate 10. Luminescent materials 3 in R, G and B are applied to the transparent collector electrode 2.
As thus described, the pair of the backside and front-side substrates 10 and 1 are held with spacers or the like (not shown) and are sealed with a vacuum space 4 sandwiched therebetween.
The two types of electrodes, i.e., the bottom electrodes 11 and the top electrodes 15 are required on the backside substrate 10 to serve as electrodes for driving the flat panel display device utilizing electron emission devices, and those electrodes are configured to be orthogonal to each other in order to drive the devices in the form of a matrix. As a result, the top electrodes 15 and bottom electrodes 11 are extended to dispose ends thereof as pickup sections on two sides of the backside substrate 10. The electrodes are connected to the outside at the pickup sections on the two sides. Since high voltage electrodes 2 for accelerating emitted electrons are required on the front-side substrate 1 facing the backside substrate 10 in parallel therewith, pickup sections of the high voltage electrodes 2 are provided and connected to the outside on a side of the front-side substrate 1 which is not in a face-to-face relationship with the two sides on which ends of the bottom electrodes 11 and top electrodes 15 are present. Thus, an assembled FED has a configuration in which the three types of electrodes, i.e., the bottom electrodes 11, top electrodes 15, and collector electrodes 2 are picked up at the three pickup sections on the three sides.
Since three sides of panels must be used in the conventional method for picking up FED electrodes as thus described, electrode pickup sections undesirably overlap each other on three sides when they are assembled into a unit. When panels are assembled into a unit, sides of the panels must be tightly combined with each other, and measures must be taken to prevent any overlap between electrode pickup sections, which makes the assembly process very much difficult.
The present invention has been conceived taking the above situation into consideration, and it is an object of the invention to provide flat panel display devices which can be combined into a unit to serve as a large display device.
A flat panel display device according to the invention comprises an emitting region constituted by a plurality of first electrodes provided on a substrate and extending in parallel, a plurality of second electrodes provided on the first electrodes and extending substantially perpendicularly to the first electrodes, and a plurality of emission devices for emitting electrons or light respectively connected to a plurality of intersections between the first and second electrodes and arranged on the substrate and comprising a peripheral region surrounding the emitting region on the substrate, characterized in that the first and second electrodes and a group of second external repeating terminals are collectively arranged side by side in a part of the peripheral region.
In one aspect of the flat panel display device according to the invention, said first external repeating terminals are ends of said first electrodes and wherein said second external repeating terminals are respectively connected to said second electrodes in said emitting region and are provided side by side along said first external repeating terminals.
In another aspect of the flat panel display device according to the invention, said first external repeating terminals and said second external repeating terminals are alternately provided side by side.
In a further aspect of the flat panel display device according to the invention, said substrate is a backside substrate; said first electrodes are bottom electrodes; said emission devices are electron emission devices having insulator layers formed on said bottom electrodes and top electrodes; and said second electrodes are connected to said top electrodes, the display device comprising a transparent front-side substrate which faces said top electrodes of said electron emission devices on said backside substrate with a vacuum space sandwiched therebetween.
In a still further aspect of the flat panel display device according to the invention, said electron emission devices have electron supply layers constituted by a metal or semiconductor provided between said bottom electrodes and said insulator layers.
In another aspect of the flat panel display device according to the invention, said front-side substrate has collector electrodes formed on a surface thereof toward said vacuum space and luminescent layers formed on said collector electrodes.
In a further aspect of the flat panel display device according to the invention, said front-side substrate has luminescent layers formed on a surface thereof toward said vacuum space and collector electrodes formed on said luminescent layers.
In a still further aspect of the flat panel display device according to the invention, the device further comprises insulating protective films provided between said second electrodes and said insulator layers and between said second electrodes and said backside substrate.
In another aspect of the flat panel display device according to the invention, the device further comprises insulating protective films provided between said first electrodes and said second electrodes at intersections between said first electrodes and said second electrodes.
In a further aspect of the flat panel display device according to the invention, said emission devices are organic electroluminescence devices having one or more layers of an organic electroluminescence medium sequentially formed between said first and second electrodes.
In a still further aspect of the flat panel display device according to the invention, said substrate and said first electrodes are transparent.
In another aspect of the flat panel display device according to the invention, said first electrodes comprise a plurality of transparent electrodes associated with each of said organic electroluminescence devices and a metal bus line for electrically connecting said transparent electrodes.
In a further aspect of the flat panel display device according to the invention, said second electrodes are transparent.
In a still further aspect of the flat panel display device according to the invention, said emitting region is in a rectangular configuration and wherein the first and second external repeating terminals collectively provided side by side in a part of said peripheral region are located on one side of said rectangle.
In another aspect of the flat panel display device according to the invention, said first and second external repeating terminals have an external terminal exposed to the outside.